Autodesk Building Systems 2006--MEP for Big Projects

Autodesk's AutoCAD-based tool for mechanical, electrical and plumbing design shows the polish of a mature product, but be sure to give it enough system horsepower.

Autodesk Building Systems, like Architectural Desktop, is built on the AutoCAD engine. It's perfect for mechanical, electrical and plumbing designs, as well as for working on fire-protection issues. Although it comes with plenty of symbols that can be used in brick-and-stick construction, it's meant for big projects. The files are, of course, compatible with Architectural Desktop; one project can be designed at multiple seats using both products at the same time. VIZ Render is included for truly magnificent rendered output.

Autodesk building systems 2006

Now that Autodesk Revit Building supports ACIS solid models, Building Systems users can share projects with Revit Building seats as well. Of course, Building Systems exports to unadorned AutoCAD DWG for consultants and others using different AutoCAD versions. Users can also export data (in gbXML, usually) to third-party analysis programs.

After years of evolution (this is the sixth major release of AutoCAD-based building systems software) and some exposure to Autodesk's Revit series, Building Systems has the glistening polish of a mature product. Symbols that represent building-system components (figure 1) "snap together" in an intelligent way. The intelligent snap even works with flexible ductwork!

Figure 1. Autodesk Building Systems 2006 searches for the right part in a catalog.

A suite of built-in and add-on engineering tools analyze fluid and air flows, energy balances and electrical loads. It's easy to create new objects or modify existing ones from a large catalog (figure 2). Within-symbol parametric design is possible. A display manager lets you view the model in many ways, without creating new drawings for each view.

Figure 2. The catalog editor changes symbol properties. Update the catalog to propagate the changes through the project.

The package is easily capable of handling systems such as those found in buildings and even in manufacturing plants. But Building Systems is not meant for actually designing production processes—there are specialized programs for that.

Design Histories

The worksheets for objects used are intuitive and keep track of engineering design histories. As with mechanical design software used in manufacturing, it's simply more convenient, accurate and intuitive (especially in multiseat and multi-office practices) to keep information such as part specs, schedules and notes on design intent available in the project itself (figure 3).

Figure 3. Users can add free-form notes to a Building Systems project to help track reasons for making certain design decisions.

As with Architectural Desktop and Revit, this functionality comes at a price. Users will want a fast machine with at least 1GB of RAM (2GB recommended) and a solid graphics card. An Autodesk white paper actually warns against making new symbols too detailed, lest they needlessly chew up processing power.

New for 2006

If you've dropped your annual subscription for Building Systems, or if you looked at it last year or earlier, be aware that this version offers some new features, many due to the evolution of AutoCAD itself.

CAD managers can now maintain project standards—styles, display settings and tools for all Building Systems 2006 (and Architectural Desktop) seats on the project (figure 4). The system synchronizes the standards from concepts to construction documentation.

Figure 4. New Building Systems tools help set project standards.

A new Workspaces function saves user-interface settings as specific themes so you can switch to settings that have the most appropriate tools in the most appropriate places for what's being done at the moment.

The new Display Themes function lets you assign colors to specific functions, such as the function or size of a room, energy needs in various areas, fire ratings and so forth. Almost any nongraphical or graphical attribute can be color-coded, and the meaning of the colors can be displayed on screen or in printouts (figure 5).

Figure 5. The style manager modifies a color theme. Note that ducts of different capacities use different colors; a capacity range has been split, and now the new split is getting its own color.

Long overdue is the ability to lay out ducts and other systems along a line with unsized parts. Then the schematic layout can be converted to an accurately sized, double-line 3D design. The connectivity between symbols has been improved to allow connections between sized and unsized portions of the layout (figure 6). That allows users to delay final detailed specs until later in the project design process. This feature alone should help reduce the disruptions that BIM (building information model) packages tend to cause when many hands work on a design. The specialists can wait until the design is more finished, but the architects still design to accommodate the expected ductwork and mechanicals. (The ability to interconnect systems—for instance, to connect the cold and hot water lines at the water heater—is also enhanced, although reassigning a connection may still change the assignment of connecting parts automatically, so be careful.)

Figure 6 . Add schematic symbols early in the design process to rough out the space the finished system might need. An "eSpace" system split physical areas of the building into sections served by specific systems.

Tweaking designs is easier. Users can directly manipulate the design on-screen without going through commands and dialog boxes. One click-and-drag stretches a duct and changes cross-sections or the z-elevation, while connecting objects stay connected. (Use this intuitive approach: If you modify a part's rotation angle or insertion point from the location tab in the MyPart Properties dialog box instead, parts connected to the modified part don't get automatically updated.)

Autodesk's clever Edit-in-View feature lets you edit or add to a small area of the design in a view other than plan. Staying focused on the specific area seems easier, too, if you use the right-mouse button to bring up command menus. New in this release is the ability to move tooltips, dimension input, and command information from the command line to the graphic interface.

Compatibility Issues

As AutoCAD evolves, it becomes ever more tempting to use xrefs. For instance, someone setting up a plumbing project in Building Systems would normally Xref an existing architectural project's files to get the walls, ceilings and so forth. This version of Building Systems even "connects" ductwork or plumbing in the live drawings with corresponding systems in the uneditable referenced drawings. But prior versions of Building Systems (until SP2 for the 2005 release) handled xrefs differently; manually referenced drawings were not included in the file structure created through Project Navigator (figure 7). Also, earlier versions of Building Systems don't support mapped drives or relative paths.

Figure 7 . Autodesk s enhanced project navigator scheme.

Autodesk warns that the referenced path of manually inserted xrefs (using the Insert/Reference command) may be lost if the referenced file moves. Use the shortcut menus in Project Navigator to attach or overlay reference files instead. That helps assure that earlier releases will find referenced files. In fact, it's a good idea to overlay xrefs instead of attaching them, unless this causes an incompatibility with third-party software. In AutoCAD-land, overlaid xrefs are meant for data sharing; the reference is only a link. Overlaid files do not display when attached or overlaid as xrefs to other drawings. Attached xrefs do display. That can cause circular xrefs and of course increased project file size.

Part symbols are stored in catalogs. Only one part catalog per domain (ducts, plumbing, electrical) can be active in a Building Systems session. The trick is to define an "all installed" catalog in the initialization script to grab all the catalogs' contents—if your computer system can handle the load.

The key question for those wedded to Autodesk software may be whether to use Building Systems 2006 or Autodesk's Revit Building 8. The decision may come down to accommodating existing or desired office workflow patterns. When I reviewed Revit last year, I found it easier to work with at the schematic level. Revit is also capable of more sophisticated engineering analysis. But Building Systems 2006 will produce more graphically detailed output, and both packages rely on exporting data to other software from Trane and GeoPraxis for detailed analysis anyway. Building Systems 2006 files also work smoothly in Architectural Desktop.

Steve Ross has been reviewing CAD software for more than 20 years.

About the Author: Steven S. Ross

Autodesk Technical Evangelist Lynn Allen guides you through a different AutoCAD feature in every edition of her popular "Circles and Lines" tutorial series. For even more AutoCAD how-to, check out Lynn's quick tips in the Cadalyst Video Gallery. Subscribe to Cadalyst's free Tips & Tools Weekly e-newsletter and we'll notify you every time a new video tip is published. All exclusively from Cadalyst!Follow Lynn on Twitter